package org.example.arrayDemo;

import java.util.Arrays;
import java.util.Date;

/**
 * 冒泡法排序
 * 动画演示：
 * https://zhuanlan.zhihu.com/p/250327672
 * https://zhuanlan.zhihu.com/p/57088609
 */
public class BubbleSort {

    // 冒泡法排序
    public static void bubbleSort(int[] arr) {
        if (arr == null || arr.length < 2) {
            return;
        }

        // 0 ~ N-1
        // 0 ~ N-2
        // 0 ~ N-3
        for (int e = arr.length - 1; e > 0; e--) { // 0 ~ e
            for (int i = 0; i < e; i++) {
                if (arr[i] > arr[i + 1]) {
                    swap(arr, i, i + 1);
                }
            }
        }
    }

    // 交换arr的i和j位置上的值
    public static void swap(int[] arr, int i, int j) {
        arr[i] = arr[i] ^ arr[j];
        arr[j] = arr[i] ^ arr[j];
        arr[i] = arr[i] ^ arr[j];
    }


    // copy数组
    public static int[] copyArray(int[] arr) {
        if (arr == null) {
            return null;
        }
        int[] res = new int[arr.length];
        for (int i = 0; i < arr.length; i++) {
            res[i] = arr[i];
        }
        return res;
    }

    // 比较两个数组是否完全相等
    public static boolean isEqual(int[] arr1, int[] arr2) {
        if ((arr1 == null && arr2 != null) || (arr1 != null && arr2 == null)) {
            return false;
        }
        if (arr1 == null && arr2 == null) {
            return true;
        }
        if (arr1.length != arr2.length) {
            return false;
        }
        for (int i = 0; i < arr1.length; i++) {
            if (arr1[i] != arr2[i]) {
                return false;
            }
        }
        return true;
    }

    // 打印输出数组
    public static void printArray(int[] arr) {
        if (arr == null) {
            return;
        }
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }

    // 启动
    public static void main(String[] args) {
        int testTime = 500000;
        int maxSize = 300;
        int maxValue = 100;
        boolean succeed = true;
        long startTime = new Date().getTime();
        for (int i = 0; i < testTime; i++) {
            int[] arr1 = Utils.generateRandomArray(maxSize, maxValue);
            //  int[] arr2 = copyArray(arr1);
            bubbleSort(arr1);
        }
        long span = new Date().getTime() - startTime;
        System.out.println("bubble:" + span + "ms");

        startTime = new Date().getTime();
        for (int i = 0; i < testTime; i++) {
            int[] arr1 = Utils.generateRandomArray(maxSize, maxValue);
            Utils.comparator(arr1);
        }
        span = new Date().getTime() - startTime;
        System.out.println("java lib:" + span + "ms");

        System.out.println(succeed ? "OK!" : "ERROR!");

        int[] arr = Utils.generateRandomArray(maxSize, maxValue);
        printArray(arr);


        bubbleSort(arr);
    }
}
